Cryocoolers are often used to cool various components to extremely low temperatures. For example, cryocoolers can be used to cool focal plane arrays in different space and airborne imaging systems. There are various types of cryocoolers having differing designs, such as pulse tube cryocoolers and Stirling cryocoolers.
Unfortunately, many cryocooler designs are inefficient and require large amounts of power during operation. For instance, cryocoolers commonly used to cool components in infrared sensors may require 20 watts of input power for each watt of heat lift at a temperature of 100 Kelvin. This is due in part to the inefficiency of compressor motors used in the cryocoolers. Compressor motors often convert only a small part of their input electrical energy into mechanical work, leading to poor overall cryocooler efficiency. While compressor motors could achieve higher efficiencies if operated over larger strokes, the achievable stroke in a cryocooler can be limited by flexure or spring suspensions used with the compressor motors.
Cryocooler compressors also often use two opposing pistons to provide compression, but these types of cryocoolers can have mismatches in the forces exerted by the opposing pistons. This leads to the generation of net exported forces. These exported forces could be due to various causes, such as mismatches in moving masses, misalignment, mismatched flexure or spring resonances, and mismatched motor efficiencies. The exported forces often need to be suppressed to prevent the forces from detrimentally affecting other components of the cryocoolers or other systems. However, such suppression typically requires additional components, which increases the complexity, weight, and cost of the systems.